rfc1865.txt
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Houser, et al Informational [Page 10] RFC 1865 EDI Meets the Internet January 1996 c) The Hypertext Transfer Protocol (HTTP) HTTP defines http-server and http-clients that comprise the World Wide Web (WWW). WWW was developed by the European Laboratory for Particle Physics (CERN) as a tool for exchanging multimedia data between researchers. Although there is also no specification for graphics in HTTP, most web browsers are graphical in nature. Mosaic, available free from the National Center for Supercomputer Applications (NCSA), provides a Graphical User Interface (GUI) that facilitates user access to information on the Internet. Mosaic interprets hypertext based information on the WWW, as well as to other linked Index/Directory services such as Archie, FTP, Gopher, and X.500 Directory information. Mosaic also supports on line Graphic Interchange Format (GIF), Joint Photographic Experts Group (JPEG), Motion Picture Experts Group (MPEG), QuickTime, and other document, image, and audio types. Vendors have developed product catalogues using Mosaic servers. d) WHOIS WHOIS servers generally offer information about the organization to which they belong. There are many WHOIS servers scattered throughout the Internet. To obtain a list of registered WHOIS servers, anonymous FTP to rtfm.mit.edu and get the file /pub/whois/whois-servers.list. You can: o run a client program on your own machine to access the WHOIS server, o telnet to a site which hosts the server, eg: telnet to whois.internic.net and type help to access the full online help o send an email message to retrieve information from the database. eg: send email to mailserv@internic.net with a command in the Subject field. Any information in the body part of message will be ignored. ie. Subject: whois <search string> Therefore, to find information on the Internic Registration Service, the subject should contain: whois internic Moreover, to obtain help information on this service you can send two separate email with the following in their subject line, respectively:Houser, et al Informational [Page 11] RFC 1865 EDI Meets the Internet January 1996 help whois help3.4. What methods exist to broadcast information across the Internet? There are also some usual methods to broadcast messages to multiple recipients as described below: a) Usenet News Usenet news is a cooperative broadcast of messages to all participants. Messages are organized into categories called newsgroups, and there are over 10,000 newsgroups carried by the major ISPs. Individual customers typically subscribe to some subset of these which is of interest to the organization. Messages are typically held for a week or two, then either archived or discarded. Some newsgroups are free form, i.e. anyone can post a message, while others are "moderated", i.e. require approval prior to posting. Though not currently used for any type of EDI, Usenet news could be used to broadcast RFQs. For example, comp.newprod is used to announce new products, and misc.jobs.wanted is used to announce job openings. b) Mailing Lists If the interest is limited, a mailing list may be used in lieu of a newsgroup. These are typically used for discussion groups or announcements of a particular nature. Mailing lists are typically open, i.e. anyone can "subscribe" by sending an email message to a server. For discussion groups, anyone can send a message to the server which is then rebroadcast to all subscribers. Since Internet email is extremely inexpensive, there is normally no charge for use of a mailing list, except for the content of e-magazines, etc. Sponsors of an email list typically provide the list as a public service. For example, a mailing list could be used to broadcast EDI RFQs, etc. Vendors might subscribe to various lists related to their product or service in order to receive messages sent by potential customers. Mailing lists could be provided by large companies for internal use, by industry organizations, or VANs. For example, a firm or government agency could sponsor various mailing lists for EDI RFQ's, new product announcements, etc. related to procurement. The organization could easily allow other potential customers to use the same mailing lists to contact vendors. All parties would benefit, and the improved access to vendors from an open mailingHouser, et al Informational [Page 12] RFC 1865 EDI Meets the Internet January 1996 list would more than offset the cost to support the mailing list server. Thus service might be available for free.3.5. What are the ways to connect to the Internet ? The following provides a general overview of connectivity options now available: a) Dedicated Connection Typically a leased telephone line is used to connect a gateway computer or Typically a leased telephone line is used to connect a gateway computer or bridge/router of a corporate LAN/WAN to the router of the Internet Service Provider's (ISP) Point-Of-Presence (POP, not to be confused with the Post Office Protocol). The connection may be of various types and speeds, e.g. modem, ISDN, DS0, or DS1 line. With a dedicated connection, the SMTP protocol is typically used to deliver email directly to a trading partners system. Also, real-time client server applications can be run directly with a trading partners system, including information transferred using the FTP and HTTP protocols. Some ISPs provide optional services even with dedicated connections. For example, store and forward email on an ISP server can be used as a backup for a direct SMTP server operated by a trading partner. The ISP may offer disk space on their FTP and HTTP servers with a high speed connection to the Internet. For example, a trading partner might use a 14.4Kb modem for dedicated email transfers and use a 1.5Mb connection operated by the ISP to distribute FTP and HTTP information. b) On-demand Connection An on-demand connection operates like a dedicated connection, except a dialup ISDN or modem connection is used. If the link remains idle for a certain period of time, the connection is dropped. Some ISPs offer dial-out capability so any inbound or outbound traffic can reestablish the link. However, many ISPs require their customers to dial-in, so only outbound traffic and regular polling will establish the link. In the latter case, store and forward would likely be used for email, and the ISP servers would be used for FTP and HTTP information.Houser, et al Informational [Page 13] RFC 1865 EDI Meets the Internet January 1996 c) Part-time Polled Connection The Unix-to-Unix Copy (UUCP) protocol is typically used for email, news, and (rarely) file transfers. A client organization periodically dials the ISP and transfers email and Usenet news for the organization, then disconnects. Typically, the client polls the ISP at regular intervals, e.g. every 20 minutes, though some ISPs dial out when a message is to be delivered. Outgoing email can be sent immediately, or queued for transmission with a specified maximum delay. A UUCP connection may be used to transfer messages to an arbitrary number of people or automated mail processing programs. A single UUCP connection may also route messages to other systems, e.g. divisions within a corporation. UUCP and store-and-forward are synonymous. Since UUCP is only used to transfer mail and news messages, interactive internet client-server applications like FTP and HTTP are not available, except using a server provided by an ISP. Thus a separate dialup account might be needed to retrieve information from other FTP or HTTP servers. UUCP might be used for automated email transfer, and a on-demand dialup connection would be used for interactive internet client applications. Though UUCP accounts imply a delay (up to the polling interval) in processing a message, many ISPs allow a customer supplied script to process messages immediately on the ISP's machine. Though UUCP can be used to transfer files directly, usually files are transferred by encoding them within an email message. Transmission within internet email messages is much more widely supported and can be gatewayed into proprietary systems. d) Dial-up Shell Account With a dial-up account, a single user with a personal computer running a terminal emulator connects to the ISP's computer. Mail readers, news readers, HTTP browsers, etc. can be run on the ISP machine. Data on the ISP machine can be transferred to the personal computer manually using a protocol like X-Modem, Z-Modem, or Kermit. The ISP's host computer may run one of the usual UNIX command line (shell) programs, or may use a custom BBS or other menu driven user interface. A proprietary client-server program may be used in lieu of a terminal emulator to provide a graphic user interface. Some of the proprietary GUI clients provide access to selected internet applications, e.g. gopher.Houser, et al Informational [Page 14] RFC 1865 EDI Meets the Internet January 1996 A dialup ISP typically has a direct internet connection, however very low cost providers might only have a UUCP connection to the Internet. Some large proprietary networks such as CompuServe do not offer a direct internet connection, and only support UUCP email and, sometimes, Usenet news gateways to the Internet. d) Personal Serial Line Internet Protocol (SLIP) or Point to Point Protocol (PPP) Account A SLIP/PPP account is also available as a cross between the on demand and dial- up. Like the on-demand account, a single user can connect to an ISP and run mail reader, news reader, FTP, HTTP browser, etc. client applications directly from a personal computer. Unlike the on-demand account, the dial-out computer functions as a client only and not a server, and would be used by a single user rather than as a gateway to a LAN. With a SLIP/PPP account, the POP (Post-Office-Protocol) protocol is used for a user's mail reader client to retrieve messages stored in the ISP's server. Unlike, UUCP, the POP servers hold mail for a single user (i.e. individual email address). With a SLIP/PPP connection any standard TCP/IP application is tied directly into the internet. Thus unlike the proprietary GUI software supplied by the ISP, any TCP/IP client application can be used. A program such as TIA (The Internet Adapter) can be run on a shell account which allows a standard UNIX shell account to function as a SLIP/PPP account. However, some ISPs do not support TIA as they charge extra for SLIP.4. Organizational Issues4.1. Why is the way we currently do EDI so limiting to its growth? There is a tendency for each organization to establish is own rules and administrative policies, leading to rising costs of dealing with multiple trading partners, each in turn with its own requirements and procedures. However, new technologies and business practices are necessary if EDI is to move beyond the 30 to 40,000 organizations presently using EDI. According to Department of Labor and Internal Revenue Service statistics, there are about 6.2 million entities with employees and about 14 million other "business" entities. A business that wants to sell chairs, for example, would have to check with many different customers to see if they had any requirements. By making it possible for a business to use a common method to look for⌨️ 快捷键说明
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